The present invention relates to a golf club head which prevents its ball hitting surface from being worn without impairing ball carry and ball hitting feeling.
Conventionally, as disclosed in Japanese Utility Model Publication No. 59-16670 of Showa, there is known a golf club head including a face part which is formed of fiber reinforced synthetic resin which is reinforced with non-metal fiber such as carbon, glass or the like and has high elasticity.
In the above golf club head, a hosel part, a sole part, a plate-like core member erected perpendicularly in the sole part and the like are formed integrally and then the fiber reinforced synthetic resin having high elasticity forming a face part is integrally applied to the core member.
According to such golf club including a face part formed of fiber reinforced synthetic resin, the ball carry is increased due to the high restitution of the fiber reinforced synthetic resin. Further, it is well known that, in a heavy metal golf club, because the specific gravity of the fiber reinforced resin is small, its face part is light and thus the gravity depth thereof is deep, so that the ball can be controlled easily.
However, because the highly elastic synthetic resin material is easy to wear due to shocks given when the ball is hit, the ball hitting surface of the face part is worn and sunken for a long period of use.
In view of this, recently, as disclosed in Japanese Utility Model publication No. 4-46777 of Heisei, Japanese Utility Model Publication No. 61-21570 of Showa, or Japanese Patent Publication No. 61-240978 of Showa, there have been proposed various golf club heads in which the ball hitting surface of the face part is reinforced.
In particular, in a golf club head disclosed in Japanese Utility Model Publication No. 4-46777 of Heisei, the core body thereof is composed of a sole part and a hosel part respectively formed of metal, and a face core part disposed integrally on the sole part; and, a highly elastic synthetic resin layer is provided at least in the ball hitting area of the front surface of the face core part except for the sole part, a metal fiber reinforced synthetic resin layer forming a face part is disposed outside the highly elastic synthetic resin layer, and then the both resin layers are united into one body.
Also, in a golf club head disclosed in Japanese Utility Model publication No. 61-21570 of Showa, as shown in FIGS. 7 and 8, an auxiliary face plate 5 is mounted such that it covers substantially the whole areas of a face part 3 of a wooden head main body 1 and a main face plate 9 is fitted into a recessed portion 7 formed in the surface of the auxiliary face plate 5. The main face plate 9 is formed of a material such as a carbon fiber reinforced synthetic resin material having a higher surface hardness than the head main body 1. Also, the auxiliary face plate 5 is formed of a material which is lower in surface hardness than the main face plate 9 but higher than the head main body 1.
Further, in a golf club head disclosed in Japanese Patent Publication No. 61-240978 of Showa, as shown in FIG. 9, a soft layer 13 formed of a rubber elastic member or a resin foaming member is provided at the front surface side of a head main body 11 and a hard layer 15 formed of fiber reinforced resin is provided at the ball hitting surface side of the soft layer 13.
However, even if the outside of the highly elastic synthetic resin layer is reinforced with the metal fiber reinforced resin layer as in the golf club head disclosed in Japanese Utility Model Publication No. 4-46777 of Heisei, the matrix synthetic resin is still easy to wear and, therefore, such reinforcement is not sufficient as means for protecting the ball hitting surface of the golf club head.
Also, since the head main body 1 of the golf club head shown in FIGS. 7 and 8 is formed of wood, when the metal face plates 5, 9 are mounted on the face part of the head, then the face part side of the head is heavy and thus the gravity depth of the head is shallow, which makes it difficult to control the golf club head.
Further, like the golf club head shown in FIG. 9, if the soft layer 13 is used in the face part, then the high restitution of the hard layer cannot be utilized but the feeling of ball hitting can also be impaired.